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2013-07-05
PIER
Vol. 140, 813-831, 2013
download: 125
A Unified Fast Solution for the Single/Interferometer/Stereo SAR Geolocation Equation Based on the Rdpc Model
Haifeng Huang Qingsong Wang
The model based on range and Doppler equations (RD model) is the most precise model for SAR geolocation, and therefore SAR geolocation based on this RD model has become more and more popular. Unfortunately, the RD method requires iterative solution, in most case, which is time-consuming and prone to poor optimization due to observation errors of parameters. In face of the huge mass of measured data from global SAR measurements, how to improve processing speed while maintaining geolocation accuracy is an important problem. This paper examines how to solve the RD geolocation equations for single, interferometric, and stereo SAR. First, the RD geolocation equations for the three kinds of systems are abstracted into a unified equation form. Second, it is determined that the RD geolocation equation can be approximated as a mapping relationship using polynomials. Then a fast solution method for the unified geolocation equation is proposed based on the Range Doppler Polynomial Coefficient Model (RDPC). Third, the accuracy loss of the RDPC model is analyzed, and the precision differences among the three kinds of system are compared. Finally, several groups of TerraSAR-X measured data for the three modes are processed using the fast algorithm. The results show that the fast algorithm greatly reduces the amount of calculation while the geolocation accuracy loss is small. Performance evaluation demonstrates that the proposed method is efficient and correct.
A UNIFIED FAST SOLUTION FOR THE SINGLE/INTERFEROMETER/STEREO SAR GEOLOCATION EQUATION BASED ON THE RDPC MODEL
2013-07-03
PIER
Vol. 140, 795-812, 2013
download: 134
Experimental Determination of the Performance of Rice Husk-Carbon Nanotube Composites for Absorbing Microwave Signals in the Frequency Range of 12.4-18 GHz
Yeng Seng Lee Mohd Fareq Bin Abd Malek Ee Meng Cheng Wei Wen Liu You Kok Yeow Muhammad Nadeem Iqbal Fwen Hoon Wee Shing Fhan Khor Liyana Zahid Mohd Fariz bin Haji Abd Malek
Composites of rice husks and carbon nanotubes (RHCNTs) are an innovation in improving the absorption of microwave signals. Rice husks, which are an agricultural waste material, have been found to possess a significant propensity for absorbing microwave signals. Studies have shown that both rice husks and carbon nanotubes (CNTs)have high percentages of carbon. Thus, in this paper, we present the results of our experimental study in which we varied the ratios of rice husks and CNTs in the composite materials and determined the dielectric properties of the composites and measured their abilities to absorb microwave signals. The experimental microwave absorber was fabricated using rice husks and CNTs, which increased the dielectric constant and the loss factor.Complex permittivity was measured using an Agilent dielectric probe.The RHCNT compositeswere investigated to determine their reflection loss and absorption performance as microwave absorbers. For the fabricated microwave absorber,we used the rectangular waveguide measurement technique to study reflection loss, transmission loss, and absorption performance in the frequency range of12.4 - 18 GHz. Carbon has an essential role in the absorber due to its ability reflect/absorb microwave signals.Thus, we compared the abilities of a pure rice-husk (PRH) absorber and RHCNT composites absorbers to absorb microwave signals.
EXPERIMENTAL DETERMINATION OF THE PERFORMANCE OF RICE HUSK-CARBON NANOTUBE COMPOSITES FOR ABSORBING MICROWAVE SIGNALS IN THE FREQUENCY RANGE OF 12.4-18 GHZ
2013-07-03
PIER
Vol. 140, 781-794, 2013
download: 157
Millimeter Wave Subharmonic Mixer Implementation Using Graphene Film Coating
George Roberto Hotopan Samuel Ver-Hoeye Carlos Vazquez-Antuna Andreea Hadarig Rene Camblor-Diaz Miguel Fernandez-Garcia Fernando Las Heras Andres
In this work, a subharmonic frequency mixer for millimeter wave applications has been designed. The mixing and multiplication phenomena are simultaneously achieved via a nonlinear component consisting in a microstrip line gap covered by a graphene film coating. The circuit structure is made up of various filters, which have been optimized to ensure high port-to-port isolation. The nonlinear behavior of the subharmonic frequency mixer has been experimentally evaluated within the 39-40.5 GHz RF frequency band. The frequency downconversion is achieved by mixing the RF signal with the second harmonic component of a 17.9 GHz LO signal. Conversion losses are minimized by generating a return path for IF, through the use of a quarter wavelength open-ended stub.
MILLIMETER WAVE SUBHARMONIC MIXER IMPLEMENTATION USING GRAPHENE FILM COATING
2013-07-02
PIER
Vol. 140, 761-779, 2013
download: 117
Body-of-Revolution-Enhanced Imaging in Ultra-Wideband SAR
Fu-Lai Liang Qian Song Hanhua Zhang Tian Jin Zhi-Min Zhou
For ultra-wideband synthetic aperture radar (UWB SAR), there often exist a lot of clutters in the image, and the weak targets are easy to be masked by them. However, using the prior scattering knowledge of targets, enhanced imaging can be realized and beneficial improvements in image quality and detection performance can be expected. In this paper, an enhanced imaging method for body of revolution (BOR) has been researched. Since the BOR target has the unique feature of aspect-invariant characteristic, the aspect scattering entropy (ASE) is proposed to describe the diversity of aspect scattering and used in the BOR-enhanced imaging method. Then the application of the proposed method in landmine detection is discussed. The experimental results show that the BOR targets are effectively enhanced and the clutters are surpressed and thus the probability of landmine detection increases under the same false alarm rate.
BODY-OF-REVOLUTION-ENHANCED IMAGING IN ULTRA-WIDEBAND SAR
2013-07-02
PIER
Vol. 140, 733-759, 2013
download: 135
Three-Dimensional Micromotion Signature Extraction of Rotating Targets in OFDM-LFM MIMO Radar
Ying Luo Qun Zhang Cheng-Wei Qiu Song Li Tat Yeo
In monostatic radars systems, only the micromotion signatures projected onto the radar line-of-sight (LOS) can be observed from echoes. As a result, the obtained micromotion signatures (e.g., the radius length of rotation) are sensitive to the radar LOS. In this paper, we propose a method for the accurate estimation of three-dimensional (3-D) micromotion signature with the orthogonal frequency division multiplexing - linear frequency modulation (OFDM-LFM) multi-input multi-output (MIMO) radar technique, which makes use of the advantages of the multi-view of MIMO radar systems and the broad bandwidth of the OFDM-LFM signals. In the proposed method, the Hough transform and Orthogonal Matching Pursuit (OMP) algorithm are introduced to extract the m-D curve features from echoes, and then the 3-D micromotion signatures of the rotating targets are obtained by solving nonlinear multivariable equation systems. The extracted 3-D micromotion signatures are no longer sensitive to the radar LOS, and can provide realistic feature information for target recognition. Simulations are given to validate the effectiveness of the proposed method.
THREE-DIMENSIONAL MICROMOTION SIGNATURE EXTRACTION OF ROTATING TARGETS IN OFDM-LFM MIMO RADAR
2013-07-02
PIER
Vol. 140, 719-732, 2013
download: 129
Far-Field Reconstruction from Near-Field Data Acquired via a Fast Spherical Spiral Scan: Experimental Evidences
Francesco D'Agostino Flaminio Ferrara Claudio Gennarelli Rocco Guerriero Massimo Migliozzi
A probe-compensated near-field - far-field (NF-FF) transformation with spherical spiral scanning, which makes possible to lower the number of needed measurements, as well as the time required for the data acquisition when characterizing quasi-planar antennas, is experimentally verified in this paper. Such a technique, based on the nonredundant representation of electromagnetic fields, has been achieved by properly applying the unified theory of spiral scans for nonspherical antennas and adopting a very flexible source modelling, formed by two circular "bowls" with the same aperture diameter but different bending radii. A two-dimensional optimal sampling interpolation formula allows one to reconstruct the NF data at any point on the measurement sphere and, in particular, at those required by the classical NF-FF transformation with spherical scanning. The reported NF and FF reconstructions, obtained from the nonredundant samples acquired on the spiral, assess the accuracy of the proposed technique.
FAR-FIELD RECONSTRUCTION FROM NEAR-FIELD DATA ACQUIRED VIA A FAST SPHERICAL SPIRAL SCAN: EXPERIMENTAL EVIDENCES
2013-06-28
PIER
Vol. 140, 681-717, 2013
download: 160
The Design of an Optical Time Steered Antenna Based on a New Integrated True Time Delay Unit
Amedeo Capozzoli Claudio Curcio Giuseppe D'Elia
In the framework of wide-band and ultra wide-band array antennas, an Optical Time Steered Antenna (OTSA) is presented, by considering the design strategies of a new True Time Delay (TTD) Control Unit in the Beam Forming Network (BFN). The unit has high reliability, low crosstalk, low switching time and potential low cost, being based on a low cost technology. Furthermore, due to its compactness and modularity, it can be easily grouped with other ones to make a control unit of large arrays. Different strategies and working configurations of the TTD control unit are presented as a trade-off among hardware complexity, insertion loss reduction and beam control capability. The design of an OTSA prototype is discussed by considering a realistic model simulating the behavior of a real world antenna and accounting for unavoidable non-realities, such as random, periodic and systematic errors introduced by each device exploited in the OTSA as well as mutual coupling between radiating elements. An optimal trimming strategy, able to compensate at best for BFN errors and based on the use of suitably located trimmers, is presented. Among other cases, to enlighten the potentialities of the OTSA, an all optical architecture providing a difference beam squint free pattern is also proposed.
THE DESIGN OF AN OPTICAL TIME STEERED ANTENNA BASED ON A NEW INTEGRATED TRUE TIME DELAY UNIT
2013-06-27
PIER
Vol. 140, 653-680, 2013
download: 155
Circularly Arced Koch Fractal Multiband Multimode Monopole Antenna
Daotie Li Jun-Fa Mao
Circularly arced Koch fractal curve (CAKC) is originally proposed. Then, a novel wire dipole is formed with Ki-iterated CAKC. The dipole is experimentally studied for fractal electrical characteristics revealing. It manifests many unique properties, such as multiband resonance at odd times of half-wavelength. In particular, it unprecedentedly presents normal mode (0.5.λ) and axial mode (1.5.λ) simultaneously. Thus, K2 CAKC wire is configured into folded monopole with circular disc ground for omni-directional and directive radiation. Five matched bands (S11≤-10 dB) are obtained within 1 GHz-10 GHz, of which f1=1.31 GHz, f2=3.14 GHz, f3=3.63 GHz, f4=4.65 GHz, and f5=7.71 GHz. Compared with conventional wire monopole (0.25.λ), this fractal monopole shows 31% height reduction. It has dipole-like patterns at f1 and f2, endfire patterns at f3 and f4 with high gain (10 dBi), and off-endfire patterns at f5. Moreover, the fractal antenna possesses compactness, lightweight, simplicity, and low cost. So, it is an attractive candidate for multiband and multifunction antennas, such as satellite antennas, of which omni-directional normal mode and directive axial mode are needed for beaconing and communication respectively.
CIRCULARLY ARCED KOCH FRACTAL MULTIBAND MULTIMODE MONOPOLE ANTENNA
2013-06-26
PIER
Vol. 140, 633-652, 2013
download: 226
Fractal Koch Multiband Textile Antenna Performance with Bending, Wet Conditions and on the Human Body
Mohd Ezwan Bin Jalil Mohamad Kamal Abd Rahim Noor Asmawati Samsuri Noor Asniza Murad Huda Abdul Majid Kamilia Kamardin Muhamad Azfar Abdullah
A multiband Fractal Koch dipole textile antenna is proposed for wearable applications. The antenna is designed to operate at 0.9 GHz, 2.45 GHz and 5.8 GHz. Denim materials as the substrate are selected aiming to obtain robustness, flexible and lightweight textile antenna. The antenna model is designed, simulated, optimized and analyzed using Microwave Studio CST software. Two types of multiband antenna prototypes are fabricated and evaluated with different conducting elements (Shield It fabric and copper foil tape). Antenna performance is observed in term of return loss, bandwidth, radiation pattern and realized gain. Three different comprehensive analyses are taking into considerations which are measurement antenna with different bending sizes, on-body measurement and under wet condition. The antenna performances are evaluated based on resonant frequency (fo) and bandwidth (BW). The antennas performance with bending on the human body (arm & forearm) is compared and investigated. A suitable placement on the body has been discovered between chest and backside of human body. The antennas have also been tested under wet conditions to ensure the stable characteristic under the influence of water.
FRACTAL KOCH MULTIBAND TEXTILE ANTENNA PERFORMANCE WITH BENDING, WET CONDITIONS AND ON THE HUMAN BODY
2013-06-26
PIER
Vol. 140, 613-631, 2013
download: 133
A New EFIE Method Based on Coulomb Gauge for the Low-Frequency Electromagnetic Analysis
Xiaoyan Y. Z. Xiong Li Jun Jiang Wei E. I. Sha Yat-Hei Lo
To solve the low-frequency breakdown inherent from the electric field integral equation (EFIE), an alternative new form of the EFIE is proposed by using the Coulomb-gauge Green's function of quasi-static approximation. Different from the commonly adopted Lorentz-gauge EFIE, the Coulomb-gauge EFIE separates the solenoidal and irrotational surface currents explicitly, which captures inductive and capacitive responses through electrodynamic and electrostatic Green's functions, respectively. By applying existing techniques such as the loop-tree decomposition, frequency normalization, and basis rearrangement, the Coulomb-gauge EFIE also can remedy the low-frequency breakdown problem. Through comparative studies between the Lorentz-gauge and Coulomb-gauge EFIE approaches from mathematical, physical and numerical aspects, the Coulomb-gauge EFIE approach shows the capability of solving low-frequency problems and achieves almost the same accuracy and computational costs compared to the Lorentz-gauge counterpart.
A NEW EFIE METHOD BASED ON COULOMB GAUGE FOR THE LOW-FREQUENCY ELECTROMAGNETIC ANALYSIS
2013-06-26
PIER
Vol. 140, 599-611, 2013
download: 135
Features of the Gouy Phase of Nondiffracting Beams
Pablo Vaveliuk Oscar Martinez Matos Gustavo Adrian Torchia
It is shown how the linear Gouy phase of an ideal nondiffracting beam of ±(k-kz)z form, with kz being the projection of the wavevector of modulus k of the plane wave spectrum onto the propagation axis z, is built from a rigorous treatment based on the successive approximations to the Helmholtz equation. The so much different families of nondiffracting beams with a continuum spectrum, as Bessel beams, Mathieu beams and Parabolic ones, as well as nondiffracting beams with a discrete spectrum, as kaleidoscopic beams, have an identical Gouy phase, which fully governs the beam propagation dynamics. Hence, a real beam whose Gouy phase is close to that linear Gouy phase in a given range, will have nondiffracting-like properties on such a range. These results are applied to determine the effective regime in which a physically realizable beam can be treated as a nondiffracting one. As an fruitful example, the Gouy phase analysis is applied to fully establish the regime in which a Helmholtz-Gauss beam propagates with nondiffracting-like properties.
FEATURES OF THE GOUY PHASE OF NONDIFFRACTING BEAMS
2013-06-26
PIER
Vol. 140, 589-598, 2013
download: 131
Creation of Super-Resolution Non-Diffraction Beam by Modulating Circularly Polarized Lightwith Ternary Optical Element
Jingsong Wei Yikun Zha Fuxi Gan
In order to obtain a super-resolution non-diffraction beam, we propose a fast searching method to design a ternary optical element combined with the circularly polarized light. The optimized results show that a beam with a spot size of 0.356λ and depth of focus of 8.28λ can be achieved by focusing with an oil lens of numerical aperture NA = 1.4 and refractive index of oil n = 1.5. The analysis reveals that the spot size of transverse component is 0.273λ, indicating that the super-resolution effect mainly comes from the transverse component. The spot size inside the media can theoretically reach down to 0.273λ because the spot size inside the media is mainly determined by the transverse component.
CREATION OF SUPER-RESOLUTION NON-DIFFRACTION BEAM BY MODULATING CIRCULARLY POLARIZED LIGHTWITH TERNARY OPTICAL ELEMENT
2013-06-21
PIER
Vol. 140, 563-588, 2013
download: 312
Modeling and Optimization Research for Dynamic Transmission Process of Balise Tele-Powering Signal in High-Speed Railways
Linhai Zhao Ying Jiang
As key components of the train control system, balise and Balise Transmission Module (BTM) cooperate with each other and fulfill the ground-train information transmission to ensure the safety and reliability of train operation. Aiming at the requirements for future developments of high-speed railway, this paper builds the model for the dynamic transmission process of the balise tele-powering signal using finite element method and electromagnetic field theory, respectively. The paper analyzes the change law of the magnetic flux density distribution within the balise receiving antenna, and derives expressions for the balise induced voltage amplitude envelope based on train speed. Then, the paper carries out the performance optimization to the existing balise system from two perspectives of the balise mounting style and the BTM mounting height. Experiments show that the proposed optimization measures can substantially enhance the system's adaptability to the ever-increasing train operation speed from the existing 448 km/h to 523 km/h. Furthermore, a potential optimization scheme with respect to the BTM mounting angle which enables huge promotion of the system performance is also discussed and proposed.
MODELING AND OPTIMIZATION RESEARCH FOR DYNAMIC TRANSMISSION PROCESS OF BALISE TELE-POWERING SIGNAL IN HIGH-SPEED RAILWAYS
2013-06-20
PIER
Vol. 140, 545-562, 2013
download: 125
Finite Ground CPW-Fed UWB Antenna Over the Metallic Cylindrical Surfaces
Rafal Lech Wojciech Marynowski Adam Kusiek
The investigation of finite ground coplanar fed ultra-wideband (UWB) antenna and the influence of its curvature and the proximity of planar and circular metalic screen on the reflection coefficients and radiation characteristics is presented. The antenna is composed of two circular coplanar strips which enclose slot aperture of similar shape and is designed on a thin and flexible substrate which allows its bending. The antenna configuration has been modeled and experimentally tested, showing good performance in 2-15 GHz frequency with return losses less than -10 dB. It is shown that the bending of antenna does not significantly affect its performance. The existence of metalic screen deteriorates its radiation pattern and reflection coefficient, however with the correct choice of the distance between screen and antenna the required level of return losses can be provided.
FINITE GROUND CPW-FED UWB ANTENNA OVER THE METALLIC CYLINDRICAL SURFACES
2013-06-19
PIER
Vol. 140, 523-544, 2013
download: 153
Electromagnetic Design and FEM Analysis of a Novel Dual-Air-Gap Reluctance Machine
Chockalingam Aravind Norhisam Bin Misron Ishak Aris Mohammad Hamiruce Marhaban Masami Nirei
The electro-magnetic torque production in the reluctance machine is highly influenced by the magnetic linkages in the air-gap area. The conventional machines derive the drawback of reduction in the air-gap area to a minimal due to influence of mechanical unbalancing thereby restricting the effective energy conversion area. In order to increase the magnetic linkage area the dual-air-gap structure is introduced. The dual-air-gap structure is realised through the division of the magnetic circuit area into two-air-gap while still maintaining the net air-gap length value. A double-rotor with single-stator structure is used to attribute the above concept. The electro-magnetic analysis of such a structure is developed and investigated through numerical analysis. In order to validate the proposed structure the electro-magnetic characteristics are compared with that of the conventional structure at similar operating conditions. The maximum torque generated by the selected dual-air-gap structure is 1.7549 Nm and for conventional structure is 1.2723 Nm. The evaluation of the proposed machine is done at the same operating conditions and it is found that the dual-air-gap structure exhibit 65% increase in average torque value in comparison with that of the conventional single-air-gap structure.
ELECTROMAGNETIC DESIGN AND FEM ANALYSIS OF A NOVEL DUAL-AIR-GAP RELUCTANCE MACHINE
2013-06-18
PIER
Vol. 140, 509-522, 2013
download: 111
A Compact Microstrip Quadruplexer Using Slotline Stepped Impedance Stub Loaded Resonators
Zhi-Peng Li Li-Juan Zhang Tao Su Chang-Hong Liang
In this paper, a novel compact quadruplexer is implemented by using slotline stepped impedance stub loaded resonators (SISLRs) in ground plane. Four folded dual-mode slotline SISLRs with one input and four output coupled line structures are designed at different frequencies for the quadruplexer operation. By properly adjusting the geometrical parameters of a single dual-mode slotline SISLR, its first two resonant frequencies can be controlled, and thus it can be utilized to implement a second-order bandpass filter when these resonant frequencies are suitably assigned. Furthermore, because the proposed quadruplexer utilizes the distributed coupling technique, a small circuit size can be obtained. As a result, the proposed quadruplexer occupies an extremely small area, i.e., 0.22λ0 × 0.25 λ0(0.36λg × 0.41λg). Finally, good agreement between measurement and EM simulation verifies the design method successfully.
A COMPACT MICROSTRIP QUADRUPLEXER USING SLOTLINE STEPPED IMPEDANCE STUB LOADED RESONATORS
2013-06-18
PIER
Vol. 140, 491-508, 2013
download: 105
Non-Linear Optimization of an Injection Locked High Efficiency VCO with Arbitrarily Width Modulated Microstrip Line Networks
Marta Gonzalez Corredoiras Samuel Ver-Hoeye Miguel Fernandez-Garcia Carlos Vazquez-Antuna George Roberto Hotopan Rene Camblor-Diaz Fernando Las Heras Andres
In this work a non-linear efficiency optimization method for its application to an Injection-Locked High Efficiency Voltage Controlled Oscillator is presented. The proposed approach is based on the control of the harmonic content of the oscillator autonomous signal, which is accomplished through the use of an Auxiliary Generator and several multi-harmonic loads based on Arbitrarily Width-Modulated Microstrip Lines. The presented technique has been applied to the design of a 2.5 GHz high efficiency Voltage Controlled Oscillator, which has been manufactured and experimentally characterized, obtaining a good agreement between the simulated and measured results.
NON-LINEAR OPTIMIZATION OF AN INJECTION LOCKED HIGH EFFICIENCY VCO WITH ARBITRARILY WIDTH MODULATED MICROSTRIP LINE NETWORKS
2013-06-17
PIER
Vol. 140, 471-490, 2013
download: 114
Degree of Depolarization of Quantization Hermite-Gaussian Beam in a Turbulent Atmosphere
Licheng Zhang Yixin Zhang Yun Zhu
Based on quantum Stokes operators and non-Kolmogorov spectrum model of index-of-refraction fluctuation, the analytical formulas for the quantum degree of depolarization of quantization Hermite-Gaussian (QHG) beams propagating in a turbulent atmosphere slant channel are derived. The nonclassical polarization properties of QHG beams propagating in turbulent atmosphere are studied numerically. It is found that the polarization fluctuations of QHG beams are dependent of the turbulence factors such as spectrum powerlaw exponent, refractive index structure parameter at the ground and zenith angle. The degree of depolarization of QHG beams has a saltation and reaches the minimum value at spectrum power-law exponent α = 11/3, the refractive index structure parameter at the ground of the turbulent atmosphere slightly affects the polarization degree of QHG beams which have travelled a long distance, and the change of polarization degree decreases with the increasing zenith angle. Furthermore, the numerical simulations show that QHG beams with higher photonnumber level, lower beam order, shorter wavelength are less affected by the turbulence. These results indicate that One can choose low-order QHG beams with wavelength λ = 690 nm as optical carrier, increase photon number, set the size of transmitting aperture ω0 as about 0.1 m, and detect communication signals at the central region of beams to improve the performance of a polarization-encoded free-space quantum communication system.
DEGREE OF DEPOLARIZATION OF QUANTIZATION HERMITE-GAUSSIAN BEAM IN A TURBULENT ATMOSPHERE
2013-06-16
PIER
Vol. 140, 457-469, 2013
download: 115
Multi-Band Negative Refractive Index in Ferrite-Based Metamaterials
Ke Bi Ji Zhou Xiaoming Liu Chuwen Lan Hongjie Zhao
A multi-band ferrite-based metamaterial has been investigated by experiments and simulations. The negative permeability is realized around the ferromagnetic resonance (FMR) frequency which can be influenced by the saturation magnetization 4πMs of the ferrites. Due to having multiple negative permeability frequency regions around the multiple FMR frequencies, the metamaterials consisting of metallic wires and ferrite rods with various 4πMs possess several passbands in the transmission spectra. The microwave transmission properties of the ferrite-based metamaterials can be not only tuned by the applied magnetic field, but also adjusted by the 4πMs of the ferrite rods. A good agreement between experimental and simulated results is demonstrated, which confirms that such a ferrite-based metamaterial possesses a tunable multi-band behavior. This approach opens a new way for designing multi-band metamaterials.
MULTI-BAND NEGATIVE REFRACTIVE INDEX IN FERRITE-BASED METAMATERIALS
2013-06-11
PIER
Vol. 140, 439-455, 2013
download: 115
Second-Order Formulation for the Quasi-Static Field from a Horizontal Electric Dipole on a Lossy Half-Space
Mauro Parise
In a recent study, we proposed improved quasi-static expressions for the electromagnetic field components excited by a vertical electric dipole lying on the surface of a flat and homogeneous lossy half-space. The present paper introduces an analytical approach to derive analogous formulas for the case of the horizontal electric dipole. The procedure is based on the expansion of the integral representations for the fields into power series of the ratio between the wavenumbers in free-space and in the conducting medium. Later, the terms in the expansions up to the second order can be reduced to known tabulated integrals. Numerical results are presented to illustrate the improvement in accuracy that follows from using the second-order approximations for the fields in place of the zeroth-order ones. In the quasi-static frequency range and beyond, use of the new formulation makes it possible to reduce the maximum relative error in the calculation of the fields from about 23% down to less than 7%.
SECOND-ORDER FORMULATION FOR THE QUASI-STATIC FIELD FROM A HORIZONTAL ELECTRIC DIPOLE ON A LOSSY HALF-SPACE